Piezoelectric vibrating piece and piezoelectric vibrating device

Abstract

A piezoelectric vibrating piece having a first and a second surface at an opposing side of the first surface is comprised of an piezoelectric piece having designated coefficient of thermal expansion; a first electrode film having bigger coefficient of thermal expansion than the designated coefficient of thermal expansion and formed on the first surface; and a second electrode film having smaller coefficient of thermal expansion than the designated coefficient of thermal expansion and formed on the second surface.

1. A piezoelectric vibrating piece having a first surface and a second surface at an opposing side of the first surface comprising:
 a piezoelectric piece having a designated coefficient of thermal expansion; 
 a first electrode film having a bigger coefficient of thermal expansion than the designated coefficient of thermal expansion and formed on the first surface; and 
 a second electrode film having a smaller coefficient of thermal expansion than the designated coefficient of thermal expansion and formed on the second surface. 
 
   
   
     2. The piezoelectric vibrating piece according to  claim 1 , wherein the first electrode film is formed by a first thickness and the second electrode film is formed by a second thickness having a designated ratio to the first thickness. 
   
   
     3. The piezoelectric vibrating piece according to  claim 1 , wherein the first and second electrode films are symmetric shape across a piezoelectric piece and have the same dimensions. 
   
   
     4. The piezoelectric vibrating piece according to  claim 1 , where in the first electrode film is formed between the electrode piece through a third electrode film. 
   
   
     5. The piezoelectric vibrating piece according to  claim 2 , where in the first electrode film is formed between the electrode piece through a third electrode film. 
   
   
     6. The piezoelectric vibrating piece according to  claim 3 , where in the first electrode film is formed between the electrode piece through a third electrode film. 
   
   
     7. The piezoelectric vibrating piece according to  claim 4 , wherein the first electrode film is a gold film and the second electrode film is an aluminum film. 
   
   
     8. The piezoelectric vibrating piece according to  claim 4  wherein the first electro film comprises copper. 
   
   
     9. The piezoelectric vibrating piece according to  claim 5 , wherein the first electrode film is a gold film and the second electrode film is an aluminum film. 
   
   
     10. The piezoelectric vibrating piece according to  claim 6 , wherein the first electrode film is a gold film and the second electrode film is an aluminum film. 
   
   
     11. The piezoelectric vibrating piece according to  claim 5 , wherein the third electrode film comprises one of: a tungsten (W) layer, a nickel (Ni) layer, a nickel tungsten layer or a titanium (Ti) layer. 
   
   
     12. The piezoelectric vibrating piece according to  claim 2 , wherein the first and second electrode films are symmetric shape across a piezoelectric piece and have the same dimensions. 
   
   
     13. The piezoelectric vibrating piece according to  claim 12 , where in the first electrode film is formed between the electrode piece through a third electrode film. 
   
   
     14. The piezoelectric vibrating piece according to  claim 13 , wherein the first electrode film is a gold film and the second electrode film is an aluminum film. 
   
   
     15. The piezoelectric vibrating piece according to  claim 13  wherein the first electro film comprises copper. 
   
   
     16. The piezoelectric vibrating piece according to  claim 13 , wherein the third electrode film comprises one of: a tungsten (W) layer, a nickel (Ni) layer, a nickel tungsten layer or a titanium (Ti) layer. 
   
   
     17. A package comprising:
 a piezoelectric vibrating piece having a first surface and a second surface at an opposing side of the first surface, said piezoelectric vibrating piece having a designated coefficient of thermal expansion; 
 a first electrode film having a bigger coefficient of thermal expansion than the designated coefficient of thermal expansion and formed on the first surface; 
 a second electrode film having a smaller coefficient of thermal expansion than the designated coefficient of thermal expansion and formed on the second surface; and 
 a cover sealing the piezoelectric vibrating piece within the package and capable of sustaining a vacuum state within the package. 
 
   
   
     18. The package as recited in  claim 17 , wherein the first electrode film is formed by a first thickness and the second electrode film is formed by a second thickness having a designated ratio to the first thickness. 
   
   
     19. The package as recited in  claim 17 , wherein the first and second electrode films are symmetric shape across a piezoelectric piece and have the same dimensions. 
   
   
     20. The package as recited in  claim 17 , where in the first electrode film is formed between the electrode piece through a third electrode film.